Nitric oxide production in the exhaled air of patients with pulmonary tuberculosis in relation to HIV co-infection.
BACKGROUND
Nitric oxide (NO) is essential for host defense in rodents, but the role of NO during tuberculosis (TB) in man remains controversial. However, earlier observations that arginine supplementation facilitates anti-TB treatment, supports the hypothesis that NO is important in the host defense against TB. Local production of NO measured in fractional exhaled air (FeNO) in TB patients with and without HIV co-infection has not been reported previously. Thus, our aim was to investigate levels of FeNO in relation to clinical symptoms and urinary NO metabolites (uNO).


METHODS
In a cross sectional study, FeNO and uNO were measured and clinical symptoms, chest x-ray, together with serum levels of arginine, tumor necrosis factor alpha (TNF-alpha) and interleukin 12 (IL-12) were evaluated in sputum smear positive TB patients (HIV+/TB, n = 36, HIV-/TB, n = 59), their household contacts (n = 17) and blood donors (n = 46) from Gondar University Hospital, Ethiopia.


RESULTS
The proportion of HIV-/TB patients with an increased FeNO level (> 25 ppb) was significantly higher as compared to HIV+/TB patients, but HIV+/TB patients had significantly higher uNO than HIV-/TB patients. HIV+ and HIV-/TB patients both had lower levels of FeNO compared to blood donors and household contacts. The highest levels of both uNO and FeNO were found in household contacts. Less advanced findings on chest x-ray, as well as higher sedimentation rate were observed in HIV+/TB patients as compared to HIV-/TB patients. However, no significant correlation was found between FeNO and uNO, chest x-ray grading, clinical symptoms, TNF-alpha, IL-12, arginine levels or sedimentation rate.


CONCLUSIONS
In both HIV negative and HIV co infected TB patients, low levels of exhaled NO compared to blood donors and household were observed. Future studies are needed to confirm whether low levels of exhaled NO could be a risk factor in acquiring TB and the relative importance of NO in human TB.
Idh
Jonna
J
Department of Medical Microbiology, Faculty of Health Sciences, Linköping University, 58185 Linköping, Sweden. jonid300@student.liu.se
Westman
Anna
A
Elias
Daniel
D
Moges
Feleke
F
Getachew
Assefa
A
Gelaw
Aschalew
A
Sundqvist
Tommy
T
Forslund
Tony
T
Alemu
Addis
A
Ayele
Belete
B
Diro
Ermias
E
Melese
Endalkachew
E
Wondmikun
Yared
Y
Britton
Sven
S
Stendahl
Olle
O
Schön
Thomas
T
D000293:Adolescent; D000328:Adult; D001120:Arginine / Q000097:blood; D001782:Blood Donors; D003430:Cross-Sectional Studies; D005002:Ethiopia; D045853:Exhalation; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000378:metabolism*; D006801:Humans; D018664:Interleukin-12 / Q000097:blood; D008168:Lung / Q000378:metabolism*; D008297:Male; D009566:Nitrates / Q000652:urine; D009569:Nitric Oxide / Q000378:metabolism* / Q000652:urine; D009573:Nitrites / Q000652:urine; D014397:Tuberculosis, Pulmonary / Q000150:complications / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D055815:Young Adult
D009566:Nitrates; D009573:Nitrites; D014409:Tumor Necrosis Factor-alpha; D018664:Interleukin-12; D009569:Nitric Oxide; D001120:Arginine